The Collaborative International Dictionary of English v.0.48:

Capillary \Cap"il*la*ry\, n.; pl. Capillaries.
   1. A tube or vessel, extremely fine or minute.
      [1913 Webster]

   2. (Anat.) A minute, thin-walled vessel; particularly one of
      the smallest blood vessels connecting arteries and veins,
      but used also for the smallest lymphatic and biliary
      vessels.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Capillary \Cap"il*la*ry\ (k[a^]p"[i^]l*l[asl]*r[y^] or
   k[.a]*p[i^]l"l[.a]*r[y^]; 277), a. [L. capillaris, fr.
   capillus hair. Cf. Capillaire.]
   1. Resembling a hair; fine; minute; very slender; having
      minute tubes or interspaces; having very small bore; as,
      the capillary vessels of animals and plants.
      [1913 Webster]

   2. Pertaining to capillary tubes or vessels; as, capillary
      action.
      [1913 Webster]

   Capillary attraction, Capillary repulsion, the apparent
      attraction or repulsion between a solid and liquid caused
      by capillarity. See Capillarity, and Attraction.

   Capillarity tubes. See the Note under Capillarity.
      [1913 Webster]

WordNet (r) 3.0 (2006):

capillary
    adj 1: of or relating to hair
    2: long and slender with a very small internal diameter; "a
       capillary tube" [syn: capillary, hairlike]
    n 1: a tube of small internal diameter; holds liquid by
         capillary action [syn: capillary, capillary tube,
         capillary tubing]
    2: any of the minute blood vessels connecting arterioles with
       venules [syn: capillary, capillary vessel]